Trunkamide A is a cyclic heptapeptide cyclo[D-Phe-Tzn-Thr(rPr)-Ser(rPr)-Ile-Ala-Pro] isolated from the colonial ascidian Lissoclinum sp. Trunkamide A was first isolated by Bowden and co-workers (Carroll, A. R.; Coil, J. C.; Bourne, D. J.; McLeod, J. K.; Zabriskie, T. M.; Ireland, C. M.; Bowden, B. F. Aust. J. Chem. 1996, 49, 659-667) but the absolute configuration of the stereocentre exocyclic to the heterocyclic ring was assigned to the L-configuration. More recently Wipf and co-workers have first demonstrated that the initial assignation was erroneous (Wipf, P.; Uto, Y. Tetrahedron Lett. 1999, 40, 5165-5169) and later demonstrated that the stereocentre at C(45) has a D-configuration (Wipf, P.; Uto, Y. J. Org. Chem. 2000, 65, 1037-1049).
Thus, the structure of trunkamide A is:

The D-Phe-Tzn is formed from two amino acids, which we refer to as amino acids one and seven of the cycloheptapeptide, where the D-Phe is amino acid seven.
Trunkamide A has promising antitumor activity and is the subject of WO 9739025.
In the article J. Org. Chem. 2000, 65, 1037-1049, Wipf and co-workers provide a synthesis of trunkamide A which involves a ring closure in solution between alanine and isoleucine to form a cycloheptapeptide having an oxazoline in place of the thiazoline ring. Trunkamide A is then obtained by further processing. The authors mention that they explored other possibilities for ring closure, such as the proline/phenylalanine amide, but they were unable to provide a viable alternative.
A further synthesis in solution by McKeever and Pattenden of trunkamide A is now also to be seen in Tetrahedron Letters 42 (2001) 2573-2577.